Constant-current transformer



L. ARNOLD.

CONSTANT CURRENT TRANSFORMER.

APPLICATION HLED MAR. 14, 1918.

1,390,074. PatentedSept. 6,1921..

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Jli lllllllllllliilllllfllfl inventor. Lgman Arnold,

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um'reo ,STATES Lynn: ,lmnonn,

PATENT OFFICE.

orfLYNn, massacnusnrrs, nssronon 'ro GENERAL ELECTRIC comrm, A conromrron or NEW YORK.

CONSTAN '1 -CURRENT TRANSFORMER.

Specification of Letters Patent.

Patented Sept. 6, 1921.

Application filed March 14, 1918. Serial No. 222,292.

sators closely resemble constant current.

transformers althou h the relatively movable windings are e ectrically connected.

The practlce common prior to my invention, very generally, almost universally, requires counterbalancin weights to partially counterbalance the welght of the movable coil or coils in these devices. These counterbalancing weights have various disadvantages, audit is the principal object of my invention to provide a constant current transformer (or analogous device) which requires a minimum or substantially no counterb-alancing weight.

To this end I incline the transformer so that the .movable coil or coils move at an angle to the vertical rather than vertically as heretofore, the inclination, being such thatthe desired current control is obtained substantially wholly, or at least in great part, by the repulsion between the windings and the pull of gravity on the movable windm s.

It will be readily understood that the effect of gravity tending to move the windings together is reduced as the transformer departs farther from the usual vertical position. In order that the transformers may be inclined, positive guiding means for the movable windings are substituted for the cords which have been almost universally used for supporting the movable coils prior to my invention. Any guiding means is satisfactory which maintains the movable winding in the desired path and allows it to move under the influence of gravity and the repulsion between the windings without introducing too much frictional restraint.

It should be understood that whereas in the above, and hereinafteras well, I seem.

mostly to consider the entire elimination of the counterbalancing weight, the entire elimination of this weight is not strictly an essential of my invention. It is diflicult in deslgning a constant current transformer, to accuratelycalculate the force of the repulsion between the windings, as well as the friction of the supporting or guiding means for the movable winding, and the other factors upon which the accurate determination of the current depends; sometimes also an adjustable weight will be found desirable in order that the value of the current may be changed at will. I contemplate therefore that, in many cases, weights will be used in devices embodying my invention, sometimes to counterbalance the pull of gravity on the movable windings to some extent, sometimes, to add to the effect of gravity on the movable windings. Inclining the core tends, at least, to reduce the effect of gravity, to eliminate or reduce the weight, simplifies the construction, and benefits the operation. Y

In the accompanying drawing and the following description, I have illustrated and described in some detail the best embodiment of my invention of which I am now aware. Figure 1 is an elevation of a constant current transformer embodying my invention, the transformer being inclosed in a protecting tank or case which is cut away to show the transformer therein. Fig. 2 is another elevation of the transformer of Fig. 1, looking at the device from the left of Fig. 1.

In Fig. 1, the tank or casing '10 is carried by a suitable supporting device 11. Within this tank or casing, is the transformer which embodies my invention This transformer, referring to both Figs. 1 and 2, comprises a core of three legs 12, 13 and 14, the windings beingabout the middle leg 13. The axis of the middle or winding leg is substantially a right line; each of the outer legs 12 and 14 and the corresponding connecting yokes 15 completes a magnetic circuit through the middle or winding leg 13. About the winding leg 13 and adjacent one end thereof, is fixed one of the coils 19 of the windings. The movable coil 20 comprises the remainder of the windings. Core clamps 21 and 22, at opposite ends of the core, are connected together by the bolts 23 which, together with. the core clamps 21 and 22, hold the parts of the core in place. The core clamp 22, which has an extension 22; as illustrated, provides a base from which the entire transformer is carried. The movable coil 20 is rigidly attached to a frame 27 pivoted at the shaft 28; this frame 27 is, in efi'ect,'a pivoted arm which positively guides and directs the movement of the movable coil or winding 20. The shaft 28 is carrier by extensions 29 from the upper core clamp 21. This matter of positively supporting or guiding or directing the movement of the movable winding of a constant current transformer (or analogous device) is claimed in my co-pending application, Serial No. 202,758, filed on or about the 19th day of November, 1917.

It will be observed, particularly from Fig. 1, that the transformer is disposed at an angle to the vertical; correspondingly the movable winding 20 is pivoted by the arm 27, to move in a path which is substantially a right line at an angle to the vertical as it is repelled from the fixed winding 19 or moved toward the same by gravity. The operation of this transformer is substantially like that of constant current transformers heretofore known. The windings 19 and 20 repel each other, and the winding 20 tends to move from the winding 19 under this repulsion; at the same time, gravity tends to move the winding 20 toward the winding 19. The effect of gravity on the movable winding 20 is not, however, so great as on the winding in a corresponding transformer made according to the prior practice since the winding 20 moves in a path at an angle to the vertical. Preferably this angle is so chosen that substantially all weights, that is, both counterbalancing weights and weights increasing the effect of gravity on the movable winding 20 are eliminated as above indicated. The exact angle in any case will be determined by the current desired for the load, the repulsion between the fixed and movable windings and the other features given by the particular design, being so in this art, that the desired valve of current is obtained.

While I have described the principle of my invention and the best mode I have con templated for applying this principle, other modifications will occur to those skilled in this art and I aim in the appended claims to cover all modifications which do not involve a departure from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A constant current transformer, comprising a core having a substantially rectilinear winding leg, fixed and movable windings on said leg, and means for pivotally suspending the movable winding from the core on an axis perpendicular to said leg, said core being tilted to have its winding leg inclined to the vertical in a plane perpendicular to said axis of suspension.

2. A constant current transformer, com prising a core having a substantially rectilinear winding leg, fixed and movable windings on said leg, and means for pivotally suspending the movable winding from the core from points at each side of the winding leg on an axis perpendicular to said leg and offset from the windings; said core being tilted to have its winding leg inclined to the vertical in a plane perpendicular to said axis of suspensio 8. A constant current transformer comprlslng a core having a winding leg, the axis of WhlCll is generally a right line at an angle to the vertical, and having another leg and yokes completing a magnetic circuit through said winding leg, a primary winding and a secondary winding about said winding leg, one of said windings being fixed relatively to said core, and means positively directing the movement of the other of said windings toward and from the fixed winding along said winding leg.

' In witness whereof, I have hereunto set my hand this 8th day of March, 1918.

- LYMAN ARNOLD. 

